Standard tools and methods for use in the completion of a wellbore are well known. Generally, perforations or ports are provided within cased wellbores for delivery of fluid treatment to the surrounding formation. Often, the completion of a wellbore requires fracturing of the formation by forcing proppant-laden fluid through the ports or perforations at high pressures. To efficiently isolate delivery of the fluid treatment to a particular wellbore region, sealing devices such as bridge plugs, friction cups, inflatable packers, and straddle packers are commonly used to isolate portions of the wellbore during fluid treatment. These devices are exposed to varying conditions during use, and debris accumulation around the tool assembly is a concern. When a sealing device is exposed to high fluid pressure differentials along its length, for example during an isolated fracturing operation, equalization of the pressure differential may cause damage to the sealing device. For example, following a fracturing operation, hydraulic pressure equalization across the sealing device will usually result in an immediate surge of fluid from the stimulated perforations or ports. This equalization surge in fluid flow will carry significant amounts of formation debris and sand such that, debris is likely to settle over and about the sealing device, or within other portions of the tool assembly. This may result in tool damage, or in the tool assembly becoming lodged within the wellbore. Increased pressure differential, sudden equalization, and any delay in removal of the tool assembly from the equalized segment further increases the risk of tool damage or lodgment downhole.
Accordingly, equalization across the sealing device during fracturing of sand-laden formations poses significant risk of debris-related tool malfunction, jamming or immobility of the tool assembly, and potential loss of the well if the tool assembly cannot be retrieved.